Rats And Mice In A Medical School Laboratory

CHONGQING, CHINA – FEBRUARY 16: (CHINA OUT) Female white rats stand in a basin at an animal laboratory of a medical school on February 16, 2008 in Chongqing Municipality, China. Over 100,000 rats and mice are used in experiments every year for pharmaceutical research in the lab, where the temperature is kept at 24 degrees centigrade. (Photo by China Photos/Getty Images)